Wall and roof panel construction systems of residential or commercial buildings do not typically provide simple, efficient, and safe means of installation. Most often in these systems, extra steps must typically be added to the installation process to prevent liquid moisture, air, and heat from passing through the wall.
Constructing a wall with a weather barrier requires not only that panels be attached to framing members, but also a house wrap is unrolled and spread over the walls. The house wrap is attached to the sheathing panels with staples or button cap nails and fenestration openings for windows or doors must be cut out of the wrap and the flaps from these openings folded back and stapled down. The house wrap is often difficult to install because it is in typical nine-ft wide rolls, which can be cumbersome to maneuver by workers on scaffolding or in windy conditions. While it is important that the barrier layer shed bulk water, it should allow for the escape of water vapor. Moreover, since house wraps are only fastened at limited points, pockets or voids form between the sheathing and house wrap. If the barrier were to trap water vapor in a wall panel, the build-up of moisture could lead to rot or mold growth. Further, certain sheathing materials, such as oriented strand board (OSB), are known to irreversibly swell and warp when exposed to moisture.
Furthermore, small gaps along the edges of adjoining panels typically remain after installation assembly. These thermal gaps within the building envelope allow undesirable thermal energy entry and escape through the walls. Although house wrap can provide some protection, breaks or tears in the house wrap often form during installation or construction. Foam insulation sheathing has also been used to improve thermal resistance performance of building structures. However, insulation sheathing also presents certain limitations and challenges. In addition to frequently suffering physical damage during installation and construction, the structural properties of insulation sheathing relegates it to limited building applications. Insulation sheathing panels are typically fastened as exterior cladding to the outermost, exterior facing of the wall with nails, screws or staples. Once again, this is an extra step that must be added to the installation process. Moreover, as an additional fastened layer, pockets or voids inevitably form between it and the surface it is secured to. Moreover, most insulation sheathing can also limit external finishing options.
In addition to wall panel systems, roof panel construction systems of residential or commercial buildings do not typically provide simple, efficient, and safe means of installation. The roof of a residential or commercial building is typically constructed by attaching several roofing panels to the rafters of an underlying supporting structural frame; the panels are most often placed in a quilt-like pattern with the edge of each panel contacting the edges of adjacent panels so as to form a substantially continuous flat surface atop the structural frame.
However, problems with roofs constructed according to this method may present themselves. Like wall panels, small gaps along the edges of adjoining roofing panels remain after roof assembly. Because the roofing panels are typically installed days or even weeks before shingles are installed, it is important to have a panel system that minimizes leakage resulting from exposure to the elements until such time as the roof is completed. To prevent water from leaking through the gaps between panels, it is commonly known in the industry to put a water resistant barrier layer on top of the roofing panels (e.g., felt paper).
While it is important that the barrier layer shed bulk water, it should also allow for the escape of water vapor. If the barrier were to trap water vapor in a roofing panel, the build-up of moisture could lead to rot or mold growth that is undesirable. As mentioned previously, it is known in the art that substantial bulk water-impermeability of installed roofing panels is achieved by adding a layer of impermeable material, such as asphalt-impregnated roofing paper or felt over the external surface of the roof panels. However, while this provides additional protection against bulk water penetration, it has the disadvantage of being difficult and time-consuming to install because the paper or felt must be first unrolled and spread over the roof surface and then secured to those panels. Further, the use of a felt paper overlay often results in a slick or slippery surface, especially when wet. Additionally, when the felt paper is not securely fastened to the roof panels or becomes loose due to wind and other weather conditions or because of poor construction methods, the roof system can become very slippery and leak bulk water. Accordingly, a worker walking atop the felt paper must be careful to avoid slipping or sliding while thereon.
It is desirable for wall sheathing panels to shed precipitation, such as rain and snow, during construction so that the interior remains dry. Accordingly, there is a need in the art for wall-sheathing panels, which are resistant to bulk water but permeable to water vapor, provide improved thermal resistance and create a simplified, safe, and time-saving installation process.
Accordingly, there is also a need in the art for roofing panels, which can be conveniently fit together and yet are constructed to minimize the gaps or allow the gaps to be sealed between adjacent roofing panels to prevent or minimize the penetration of bulk water through the roof as it travels over the roof's surface. It is desirable for roofing panels to shed precipitation, such as rain and snow, during construction so that the interior remains dry.
Given the foregoing, there is a continuing need to develop improved panels for roof and wall construction that prevent or minimize the penetration of bulk water, that come pre-equipped with a water permeable barrier layer applied during manufacture, and that have improved thermal performance.